X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?p=secnet.git;a=blobdiff_plain;f=netlink.c;h=af6434feb9002c12a938a2d2923d2f92ea8b9c53;hp=5226ad1166af5517a3586d59523dc8422ae0dc75;hb=975820aa67cb8f5f89eb968ec5397305e3b77bcf;hpb=1caa23ff879cec7f8f36b32a987f0610291ef177

diff --git a/netlink.c b/netlink.c
index 5226ad1..af6434f 100644
--- a/netlink.c
+++ b/netlink.c
@@ -106,9 +106,6 @@ their use.
 #include "netlink.h"
 #include "process.h"
 
-#define OPT_SOFTROUTE   1
-#define OPT_ALLOWROUTE  2
-
 #define ICMP_TYPE_ECHO_REPLY             0
 
 #define ICMP_TYPE_UNREACHABLE            3
@@ -241,7 +238,7 @@ static struct icmphdr *netlink_icmp_tmpl(struct netlink *st,
     struct icmphdr *h;
 
     BUF_ALLOC(&st->icmp,"netlink_icmp_tmpl");
-    buffer_init(&st->icmp,st->max_start_pad);
+    buffer_init(&st->icmp,calculate_max_start_pad());
     h=buf_append(&st->icmp,sizeof(*h));
 
     h->iph.version=4;
@@ -296,6 +293,7 @@ static bool_t netlink_icmp_may_reply(struct buffer_if *buf)
     struct icmphdr *icmph;
     uint32_t source;
 
+    if (buf->size < (int)sizeof(struct icmphdr)) return False;
     iph=(struct iphdr *)buf->start;
     icmph=(struct icmphdr *)buf->start;
     if (iph->protocol==1) {
@@ -341,6 +339,7 @@ static bool_t netlink_icmp_may_reply(struct buffer_if *buf)
    */
 static uint16_t netlink_icmp_reply_len(struct buffer_if *buf)
 {
+    if (buf->size < (int)sizeof(struct iphdr)) return 0;
     struct iphdr *iph=(struct iphdr *)buf->start;
     uint16_t hlen,plen;
 
@@ -357,11 +356,11 @@ static void netlink_icmp_simple(struct netlink *st, struct buffer_if *buf,
 				struct netlink_client *client,
 				uint8_t type, uint8_t code)
 {
-    struct iphdr *iph=(struct iphdr *)buf->start;
     struct icmphdr *h;
     uint16_t len;
 
     if (netlink_icmp_may_reply(buf)) {
+	struct iphdr *iph=(struct iphdr *)buf->start;
 	len=netlink_icmp_reply_len(buf);
 	h=netlink_icmp_tmpl(st,ntohl(iph->saddr),len);
 	h->type=type; h->code=code;
@@ -384,19 +383,30 @@ static void netlink_icmp_simple(struct netlink *st, struct buffer_if *buf,
  * 3. Checksums correctly.
  * 4. Doesn't have a bogus length
  */
-static bool_t netlink_check(struct netlink *st, struct buffer_if *buf)
+static bool_t netlink_check(struct netlink *st, struct buffer_if *buf,
+			    char *errmsgbuf, int errmsgbuflen)
 {
+#define BAD(...) do{					\
+	snprintf(errmsgbuf,errmsgbuflen,__VA_ARGS__);	\
+	return False;					\
+    }while(0)
+
+    if (buf->size < (int)sizeof(struct iphdr)) BAD("len %"PRIu32"",buf->size);
     struct iphdr *iph=(struct iphdr *)buf->start;
     int32_t len;
 
-    if (iph->ihl < 5 || iph->version != 4) return False;
-    if (buf->size < iph->ihl*4) return False;
-    if (ip_fast_csum((uint8_t *)iph, iph->ihl)!=0) return False;
+    if (iph->ihl < 5) BAD("ihl %u",iph->ihl);
+    if (iph->version != 4) BAD("version %u",iph->version);
+    if (buf->size < iph->ihl*4) BAD("size %"PRId32"<%u*4",buf->size,iph->ihl);
+    if (ip_fast_csum((uint8_t *)iph, iph->ihl)!=0) BAD("csum");
     len=ntohs(iph->tot_len);
     /* There should be no padding */
-    if (buf->size!=len || len<(iph->ihl<<2)) return False;
+    if (buf->size!=len) BAD("len %"PRId32"!=%"PRId32,buf->size,len);
+    if (len<(iph->ihl<<2)) BAD("len %"PRId32"<(%u<<2)",len,iph->ihl);
     /* XXX check that there's no source route specified */
     return True;
+
+#undef BAD
 }
 
 /* Deliver a packet. "client" is the _origin_ of the packet, not its
@@ -406,6 +416,13 @@ static void netlink_packet_deliver(struct netlink *st,
 				   struct netlink_client *client,
 				   struct buffer_if *buf)
 {
+    if (buf->size < (int)sizeof(struct iphdr)) {
+	Message(M_ERR,"%s: trying to deliver a too-short packet"
+		" from %s!\n",st->name, client?client->name:"(local)");
+	BUF_FREE(buf);
+	return;
+    }
+
     struct iphdr *iph=(struct iphdr *)buf->start;
     uint32_t dest=ntohl(iph->daddr);
     uint32_t source=ntohl(iph->saddr);
@@ -523,6 +540,7 @@ static void netlink_packet_forward(struct netlink *st,
 				   struct netlink_client *client,
 				   struct buffer_if *buf)
 {
+    if (buf->size < (int)sizeof(struct iphdr)) return;
     struct iphdr *iph=(struct iphdr *)buf->start;
     
     BUF_ASSERT_USED(buf);
@@ -552,6 +570,12 @@ static void netlink_packet_local(struct netlink *st,
 
     st->localcount++;
 
+    if (buf->size < (int)sizeof(struct icmphdr)) {
+	Message(M_WARNING,"%s: short packet addressed to secnet; "
+		"ignoring it\n",st->name);
+	BUF_FREE(buf);
+	return;
+    }
     h=(struct icmphdr *)buf->start;
 
     if ((ntohs(h->iph.frag_off)&0xbfff)!=0) {
@@ -595,14 +619,19 @@ static void netlink_incoming(struct netlink *st, struct netlink_client *client,
 {
     uint32_t source,dest;
     struct iphdr *iph;
+    char errmsgbuf[50];
+    const char *sourcedesc=client?client->name:"host";
 
     BUF_ASSERT_USED(buf);
-    if (!netlink_check(st,buf)) {
-	Message(M_WARNING,"%s: bad IP packet from %s\n",
-		st->name,client?client->name:"host");
+
+    if (!netlink_check(st,buf,errmsgbuf,sizeof(errmsgbuf))) {
+	Message(M_WARNING,"%s: bad IP packet from %s: %s\n",
+		st->name,sourcedesc,
+		errmsgbuf);
 	BUF_FREE(buf);
 	return;
     }
+    assert(buf->size >= (int)sizeof(struct icmphdr));
     iph=(struct iphdr *)buf->start;
 
     source=ntohl(iph->saddr);
@@ -791,27 +820,6 @@ static void netlink_signal_handler(void *sst, int signum)
     netlink_dump_routes(st,True);
 }
 
-static void netlink_inst_output_config(void *sst, struct buffer_if *buf)
-{
-/*    struct netlink_client *c=sst; */
-/*    struct netlink *st=c->nst; */
-
-    /* For now we don't output anything */
-    BUF_ASSERT_USED(buf);
-}
-
-static bool_t netlink_inst_check_config(void *sst, struct buffer_if *buf)
-{
-/*    struct netlink_client *c=sst; */
-/*    struct netlink *st=c->nst; */
-
-    BUF_ASSERT_USED(buf);
-    /* We need to eat all of the configuration information from the buffer
-       for backward compatibility. */
-    buf->size=0;
-    return True;
-}
-
 static void netlink_inst_set_mtu(void *sst, int32_t new_mtu)
 {
     struct netlink_client *c=sst;
@@ -820,14 +828,10 @@ static void netlink_inst_set_mtu(void *sst, int32_t new_mtu)
 }
 
 static void netlink_inst_reg(void *sst, netlink_deliver_fn *deliver, 
-			     void *dst, int32_t max_start_pad,
-			     int32_t max_end_pad)
+			     void *dst)
 {
     struct netlink_client *c=sst;
-    struct netlink *st=c->nst;
 
-    if (max_start_pad > st->max_start_pad) st->max_start_pad=max_start_pad;
-    if (max_end_pad > st->max_end_pad) st->max_end_pad=max_end_pad;
     c->deliver=deliver;
     c->dst=dst;
 }
@@ -898,8 +902,6 @@ static closure_t *netlink_inst_create(struct netlink *st,
     c->ops.reg=netlink_inst_reg;
     c->ops.deliver=netlink_inst_incoming;
     c->ops.set_quality=netlink_set_quality;
-    c->ops.output_config=netlink_inst_output_config;
-    c->ops.check_config=netlink_inst_check_config;
     c->ops.set_mtu=netlink_inst_set_mtu;
     c->nst=st;
 
@@ -909,7 +911,7 @@ static closure_t *netlink_inst_create(struct netlink *st,
     c->deliver=NULL;
     c->dst=NULL;
     c->name=name;
-    c->link_quality=LINK_QUALITY_DOWN;
+    c->link_quality=LINK_QUALITY_UNUSED;
     c->mtu=mtu?mtu:st->mtu;
     c->options=options;
     c->outcount=0;
@@ -957,8 +959,6 @@ netlink_deliver_fn *netlink_init(struct netlink *st,
     st->cl.type=CL_PURE;
     st->cl.apply=netlink_inst_apply;
     st->cl.interface=st;
-    st->max_start_pad=0;
-    st->max_end_pad=0;
     st->clients=NULL;
     st->routes=NULL;
     st->n_clients=0;